Flask + Gunicorn + Nginx 部署

Flask + Gunicorn + Nginx 部署

简介

WSGI协议

Flask致力于如何生成HTML代码,而Web服务器用于处理和响应HTTP请求。Flask和Web服务器之间的通信，需要一套双方都遵守的接口协议。WSGI协议就是用来统一这两者的接口的。

WSGI容器——Gunicorn

常用的WSGI容器有Gunicorn和uWSGI，性比较而言，Gunicorn配置简单，性能优越。

Nginx

Nginx是一款轻量级的Web 服务器/反向代理服务器。

假设我们有一个todos的项目，项目结构如下：

gavinsun:python-flask-todos gavinsun$ tree
.
├── README.markdown  # 说明文档
├── requirements.txt  # 环境需求
├── test.py   # 测试文件
└── todos  #todos应用包
    ├── __init__.py
    ├── static  # 静态资源
    │   └── style.css  
    ├── templates  # 模板
    │   └── todos.html
    ├── todos.db  # 数据库文件
    ├── todos.py  # todos应用
    ├── todos.sublime-workspace
    └── wsgi.py # 用来启动todos应用
​

wsgi.py代码如下：

from todos import app
if __name__ == '__main__':
    app.run()

不使用Gunicorn，直接启动app的方法如下：

(.venv) gavinsun:python-flask-todos gavinsun$ python wsgi.py 
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 281-552-583
​

这样虽然能过运行，但是，性能太差，使用Gunicorn性能会好很多。

使用Gunicorn启动app

(.venv) gavinsun:python-flask-todos gavinsun$ pip install gunicorn
(.venv) gavinsun:python-flask-todos gavinsun$ gunicorn todos.todos:app
[2018-04-07 10:48:30 +0800] [3458] [INFO] Starting gunicorn 19.7.1
[2018-04-07 10:48:30 +0800] [3458] [INFO] Listening at: http://127.0.0.1:8000 (3458)
[2018-04-07 10:48:30 +0800] [3458] [INFO] Using worker: sync
[2018-04-07 10:48:30 +0800] [3461] [INFO] Booting worker with pid: 3461
或者
(.venv) gavinsun:python-flask-todos gavinsun$ cd todos/
(.venv) gavinsun:todos gavinsun$ gunicorn wsgi:app
[2018-04-07 10:49:46 +0800] [3465] [INFO] Starting gunicorn 19.7.1
[2018-04-07 10:49:46 +0800] [3465] [INFO] Listening at: http://127.0.0.1:8000 (3465)
[2018-04-07 10:49:46 +0800] [3465] [INFO] Using worker: sync
[2018-04-07 10:49:46 +0800] [3468] [INFO] Booting worker with pid: 3468
​

部署过程

创建专门用于部署Web应用的用户

$ useradd deploy
$ mkdir /home/deploy
$ chown deploy:deploy /home/deploy
$ usermod -a -G sudo deploy
$ passwd deploy
$ chsh -s /bin/bash deploy
​

​

准备工作，安装如下工具

sudo apt install ufw python-dev python-virtualenv python-pip git nginx supervisor
​

安装虚拟环境（一个项目对应一个虚拟环境）

$ mkdir ~/.virtualenvs && cd ~/.virtualenvs
$ virtualenv flask-todos
$ source ~/.virtualenvs/flask-todos/bin/activate
​

下载项目代码，安装requirements.txt

(flask-todos)$ mkdir ~/sites && cd ~/sites
(flask-todos)$ git clone https://github.com/alexandersimoes/flask-todos.git (flask-todos)$ cd flask-todos
(flask-todos)$ pip install -r requirements.txt
​

安装Nginx

sudo apt install nginx
​

配置Nginx

(flask-todos)$ sudo rm /etc/nginx/sites-enabled/default
(flask-todos)$ sudo nano /etc/nginx/sites-available/flask-todos
​

flask-todos配置文件如下：

server {
    listen 80;
    server_name 97.64.81.242;
​
    root /home/deploy/sites/flask-todos;
​
    access_log /home/deploy/sites/flask-todos/logs/nginx/access.log;
    error_log /home/deploy/sites/flask-todos/logs/nginx/error.log;
​
    location / {
        proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $http_host;
        proxy_redirect off;
        if (!-f $request_filename) {
            proxy_pass http://127.0.0.1:8000;
            break;
        }
    }
    location /config{
        alias /home/gavin/config/;
        autoindex on;
    }
​
    location /static {
        alias  /home/deploy/sites/flask-todos/todos/static/;
        autoindex on;
    }
}
​

创建用于保存nginx log的文件路径

 (flaskdeploy)$ mkdir -p ~/sites/flaskdeploy/logs/nginx
​

创建符号链接，启用flask-todos配置

(flaskdeploy)$ sudo ln -s /etc/nginx/sites-available/flaskdeploy /etc/nginx/sites-enabled/
(flaskdeploy)$ sudo nginx -t
(flaskdeploy)$ sudo service nginx restart
​

关于sites-available和sites-enabled的说明：

The sites-available folder is for storing all of your vhost configurations, whether or not they're currently enabled.
​
The sites-enabled folder contains symlinks to files in the sites-available folder. This allows you to selectively disable vhosts by removing the symlink.
​
You should edit files only in sites-available directory.
Do never edit files inside the sites-enabled directory, otherwise you can have problems if your editor runs out of memory or, for any reason, it receives a SIGHUP or SIGTERM.
​

总之，在sites-available中创建网站的配置文件，在sites-enabled中创建要启用的网站的配置文件的符号链接。千万不要在sites-enabled中直接创建配置文件。

使用supervisor管理 gunicorn 命令

安装

sudo apt install supervisor
​

把flask-todos启动命令添加到supervisor中进行管理

创建配置文件flask-todos

sudo vi /etc/supervisor/conf.d/flask-todos.conf
​

在flask-todos.conf中添加如下内容

[program:flask-todos]
command = /home/deploy/.virtualenvs/flask-todos/bin/gunicorn wsgi:app -w 2
directory = /home/deploy/sites/flask-todos/todos
user = deploy
​
stdout_logfile = /home/deploy/sites/flask-todos/logs/gunicorn/gunicorn_stdout.log 
stderr_logfile = /home/deploy/sites/flask-todos/logs/gunicorn/gunicorn_stderr.log 
redirect_stderr = True
environment = PRODUCTION=1
​

执行下面3条命令，如果没有报错，flask-todos将以后台服务的形式启动。

sudo supervisorctl reread
sudo supervisorctl update
sudo supervisorctl start flask-todos
​

至此，部署完毕！